The invention relates to a process for dyeing histological preparations arranged on microscope slides.
When histological preparations are examined under a microscope, dyeing is one of the most frequently used methods to differentiate the structures in cells and tissues and to render them visible through high contrast. By suitably controlling the dyeing process individual structures can be selectively emphasized.
In dyeing histological preparations for microscopic examinations, the physical and chemical properties of the structure in the cells and tissues are utilized for binding specific dyes. For histological dyes, natural dyes are used, but predominantly synthetic dyes. Most of them are diachromes, i.e. they absorb in the range of visible light; others glow only with ultraviolet radiations; they are fluorescent dyes. What is important for the dyeing process is the charge of the dyes. There are electronegative, electropositive and neutral charges. When several dyes are used, they are either applied in succession or simultaneously in a dye solution.
To date, 80% of the histological preparations were dyed by dangerous manual labor and only 20% were dyed fully automatically. The reason lies in the fact that the automatic dyeing machines offered on the market can do only one dyeing method at a time currently and have to be refitted or reprogrammed when the dyeing method is changed.
A well-known automatic dyeing machine of the "Medite" company functions according to the principle of a continuously recurring transport movement for the object slide holders, in which microscope slides with histological preparations are situated. With this transport movement the object slide holders are transported to processing stations, of which there are up to 23 in succession. One object slide holder suspended into a first position of a sprocket is conveyed by the sprocket via a specific path as far as the processing station and lowered there into a first vat with a reagent. In so doing, during the processing time an additional reciprocating motion (agitation) can be conducted. Finally the object slide holder is lowered completely into the vat and the sprocket travels back again the same path under the carrying strap of the object slide holder. As soon the starting position is reached, a second object slide holder can move up into the first position of the sprocket.
Having carried out this process step, the sprocket lifts the first object slide holder out of the reagent, holds it according to a preselectable drip period above the vat and travels then one position further to the next processing station. There the first object slide holder is lowered into the second vat; and the second object slide holder, into the first vat. According to this principle the object slide holders travel through all of the processing stations and can finally be removed at the end of the carriage. The cycle time for the transport movement can be freely chosen within a specified frame and is the same for all processing stations. Different processing times can be obtained by connecting identical processing stations serially.
Another well-known automatic dyeing machine of the "Shandon" company functions according to the revolving method. In this case 24 processing stations, which can be freely selected, are arranged in a circle. However, the order of sequence in which the processing stations can be entered is fixed by the revolving method. Above the processing stations is a cover, which can be moved up and down and rotated clockwise. The object slide holders with the preparations, which are to be dyed and are arranged on microscope slides, are suspended from this cover and transported to the processing stations. During the dyeing process the cover can be agitated. Another function of the cover is to protect against the evaporation of the reagents. The protecting function is, however, operative only in the lowered state. The processing time in the individual stations can be programmed individually for each of the 24 processing stations. It is also possible to store two different dyeing programs, which can then be called by means of a push button when needed. However, these dyeing programs cannot run simultaneously.
An automatic dyeing machine of the "Sakura" company provides a matrix-shaped arrangement of the processing stations, which can be approached by way of a triaxial controller. There exists access to each processing station, so that a dyeing operation can be conducted in any arbitrary order, but only one dyeing method can be conducted at a time.
A device for automatic dyeing of preparations for microscopic examination is known from the GB-A-2 196 428. The prior art device includes several processing stations, to which histological preparations arranged on microscope slides are conveyed in object slide holders and are subjected there to processing measures corresponding to a selectable dyeing method. The conveyor includes coupling elements, which after placing an object slide holder into a processing station can be detached from it, so that a connection with another object slide holder is enabled. The conveyor is controlled in such a manner by a controller, into which the dyeing program must be fed prior to the implementation of each dyeing operation, that it can transport, as a function of the selected dyeing method, the other object slide holders to free processing stations.
Storage of different dyeing programs, which can be called, as desired, and run simultaneously in the sense of computer-controlled optimization, is not provided.
An automatic dyeing machine is known from the document U.S. Pat. No. 3,674,040; said automatic dyeing machine comprises two rows of baths with dyeing reagents, where the rows are arranged on two levels at a time. Object slide holders can be conveyed by means of a conveyor, which can be raised and lowered and moved only in the transverse direction to the insert positions of the baths. A specific approach of the baths is not possible. Rather the baths themselves have to be moved to the corresponding insert positions, whereby the baths on each level are coupled together like a chain and can be moved jointly and whereby the transfer from one level to the other is conducted with the aid of lifts at the beginning and end of the row. In so doing, the movement sequence of the chain and that of the lifts is limited only to one direction of movement.
Between the rows of baths there is a rinsing chamber, above which object slide holders in a central position of the conveyor can drip or be immersed and rinsed.
Furthermore, it is provided that the reagents can be circulated by means of agitator blades, which can be set rotating by means of a driver, moved in from the opening side of the baths.